My first blog post on weirdness in the natural world focused on quantum physics (What Is All The Weirdness About?). This post will focus on the weirdness I see in the biological world. The way I see it, there is plenty of weirdness in this realm of the world. This should not seem so strange when you consider that biology is much more complex than what goes on at the quantum level of the universe. So, I will relate some of things I find interesting, baffling, ponderous, and just out and out strange about the biological realm.
There are between thirty to forty trillion cells that make up the average human body.¹ The Smithsonian website states it as 37.2 trillion cells.² But, the actual count is not really important, just the huge amount, to the first point I want to make.
If this is not amazing in and of itself, think about the fact that we have all these cells in our bodies carrying out all of their functions all the time. And these cells are busy busy places. There is activity going on both inside and outside the nucleus of the cell. Inside, DNA is constantly being translated to mRNA (the messenger—don’t shoot it), and when the cells divide a complete copy of the DNA is made. And, DNA is also being repaired when needed. Outside the nucleus mRNA meets up with tRNA (transfer—don’t shoot it either) at the ribosomes and strings together amino acids to make proteins, which can be enzymes that further the chemical reactions in the cell, or used for the structural components of our bodies.
In addition to these activities by the DNA and RNA there are: the mitochondrion, which produces energy for the cell in the form of ATP (a kind of energy currency); the smooth endoplasmic reticulum, which makes lipids (the main constituents of the cell wall) and helps in detoxification; the rough endoplasmic reticulum, which helps in protein production for use outside the cell; the Golgi apparatus, which works to modify proteins and for delivery outside the cell; the peroxisomes, which works to break down lipids; and lysosomes, which plays a role in protein destruction.³
So, cells—trillions of them—are teeming with activity. Yet, we are never aware of the internal workings of our cells. I feel that it is exceedingly weird that all this activity is going on, and we can never detect it. We, of course, feel some of the outcomes of many cells working together. We can, on occasion feel are heartbeat, and with a stethoscope we can hear it. One organ we are most aware of is our skin (skin is an organ). Another organ that we become aware of its activity all the time is our brain (more below) with our self-conscious awareness. And, when we pee we feel the output of our kidney cells.
Another thing of curiosity is that it appears that within seven to ten years almost all the atoms in our bodies are replaced. Some cells take longer than ten years, and DNA and certain neurons do not get replaced at all. New DNA is produced when cells divide. And while, neurons die, they are not replaced. Be warned that a lot of internet buzz will claim that all of the material in our bodies is replaced.
The best study out there from an actual scientist is from the work of Jonas Frisen. One of his studies4 looked at the amount of carbon-14 in cell tissue. It is radioactive and decays at a known rate. So measuring the ratios with non-radioactive carbon-12 can tell us how old the tissue is that contains it. When compare with the age of the person most cell tissue is younger than their age. However, certain neurons show no difference between the two ages, from which you can deduce that their cells have not had their materials replaced. This study and others also compares different types of cell and how fast they are replaced. An earlier technique that was used was radioactive tracers attached to certain atoms like calcium in finding the rates of cellular replacement. I believe the carbon-14 dating is more accurate than using the tracers.
Some ask, if my cellular parts are constantly being replace with new molecules, am I the same person? Yes, for a number of reason. One, most brain cells have no replacement going on. Two, part of what makes you you is how your brain functions and your interactions with your environment. Three, personhood is a higher level concept than cellular makeup. Four, DNA remains stable, which is often thought of as making you the person you are. While there maybe a theoretical reduction to atoms and below, we have no way of currently doing so; therefore, higher level concepts like personhoodº and higher level actions, like DNA direction of biological structure and actions are wanted to provide the best explanations,* which is what we want in the first place here.
So, while not totally true that the elements in your body are replaced in monthly or yearly cycles, it is still quite amazing. I would use the term magical if I would allow myself such usage, since I do not belief in supernatural magic. Again, like cell activity we have no conscious awareness of this replacement going. We could study one of our cells, but the feeling of it changing its materials on an ongoing basis still does not occur.
Another thing that occurs is the metabolism of food. Whereby, you ingest food, then your body breaks it down, uses it for energy and body structures with its various functions, then the waste products of the metabolized food is expelled by the body. A nice slice of pie goes in, so tasty at first, and it comes out as pooh (excuse my Britishism), not very tasty, or so I have heard.
The first thing necessary for metabolism to occur is the ingestion of food. You take a bite and chew it, where it mixes with saliva and enzymes to form a bolus, which is then swallowed. In the stomach more enzymes are added to the mix from where it travels into the small intestines (the duodenum) where the main part of digestion takes place, and the nutrients are dispersed throughout the body by the blood to be used by our cells. The liver and pancreas also play a role in the metabolism process. The body has waste products to expel once the cells are though with their work. Some is excrete by way of the kidneys in the urine, and solid waste is dump into the large intestines (the colon) where is is expelled through the bowel and out of the anus. Quite a task going on, and in human beings it can go on for over seventy years.
Then, there is plant growth via nutrients in the soil, and carbohydrates that are produced from carbon dioxide in the air utilizing sunlight in the chloroplasts. Think about a tree—a tall tree. It must transport the nutrients via its roots all the way up into the cells from root to tip (the canopy). And, what is more is these plants produce oxygen which all but certain anaerobic organisms need to survive. It was actually green algae that poisoned the air for all these earlier anaerobic organisms, but made for the massive growth of aerobic species. The anaerobic organisms went underground, so to speak, some of which are thought to have made themselves at home in other cells, becoming organelles, like the mitochondria and chloroplasts.
Biological metabolism—is it not wonderful?
There is a class organisms that are out and out weird at least from our perspective. These are called extremophiles, not all of which are single celled creatures. These organisms live in such extreme condition that would easily kill most other ones. There are single cell organisms that thrive in extreme cold, and there are heat loving ones. There are also those that seem to do quite well in what would ordinarily be poisonous conditions, like an environment with plenty of acid.
Perhaps the most interesting of all these extremophiles are the ones that live around deep sea vents, which spew sulfur dioxide. No sunlight reaches down this deep in the oceans, so single cell organisms have to extract what it needs from the sulfur dioxide and other nutrients at hand. Upon these others feed. There are worms, crabs, and other creatures that live in these rather unique ecosystems.
Then, there is the DNA shared by all organism. The DNA molecules are the same in all organism, using the same three chain code for the amino acids that get strung together in the cells to make proteins. I repeat, DNA is the same in every single living thing on earth. Plus, there are viruses (some which use RNA as their genetic material), which have a dubious claim to be living. They reproduce, but not on their own, and they have no separate metabolism.
DNA is called “the book of life” by some. In it is everything that is needed to develop and to continue to live for all organism on earth. It is all there in the DNA. How amazing. Of course, the DNA needs an environment, including the cellular environment. Their environment includes other cells and in mammals at least the womb. Without an environment DNA could do nothing, not even maintain itself. So, living things are a combination of DNA and the environment it which they are situated. The environment includes the nutrients consumed (food by human beings); this is where all the raw materials come from.
And, let me not forget about development (or morphogenesis). When a male sex cell joins with a female sex cell a zygote is formed. It then starts to divide. After a number of these divisions a blastula is formed. From here cells begin to differentiate into the ectoderm, mesoderm, and endoderm. “The ectoderm gives rise to the skin covering, to the nervous system, and sense organs. The mesoderm produces the muscles, excretory organs, circulatory organs, sex organs (gonad), and internal skeleton. The endoderm lines alimentary canal and gives rise to the organs associated with digestion and, in chordates, with breathing.” Mammals continue to develop in the placenta. Most mammals are born immature and continue to develop after birth. Human beings are born the most premature, especially brain tissue. But, eventually if all goes right through being a baby, child, preteen, and adolescent they become adults. There are insects, which developed in stages: egg, larvae, pupae, and adult.
We are wonderfully made, not by god, but by our genetic inheritance in interaction with the environment, initially in the womb. Two separate cells join and become an adult animal having differentiated into all the different types of cells and organs. It is absolutely amazing. (For a much fuller description of morphogensis see “Animal Development” @ https://www.britannica.com/science/animal-development/Adaptations-in-mammals, where I got my information quoted in the previous paragaph.)
Here is one that is totally mind blowing to me. The amount of organism living on and in us is greater than the number of the cells that make up our bodies—all 37.2 trillion of them. We have mites and other small creatures, plus bacteria on the outside of our bodies. Are guts are populated by bacteria, some of which are so beneficial that we could not do without them, helping in digestion and giving a boost to our immune systems. “The worms go in, the worms go out, they eat your guts, and they spit them out.”
Oddly enough, there is evidence that autoimmune diseases like Crohn’s, which affects our guts with severe symptoms and are at times incapacitating, may be caused in part by not having worms.^ Evidently, those in Africa, where internal worms are endemic, never contract the disease. It can be treated successfully by being given worms through the skin or in a slurry. It also appears that appendisitis is rare in the developing world or those places where diarrheal diseases are endemic. Here the appendix is theorized to dump its host of bacteria into our guts to repopulate them after suffering from diarrhea, hence where this does not occur the bacteria can build up in the appendix and burst sending the bacteria into the body were it can cause a person to go septic—not so good if you want to live. (A pretty good book about all this is The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are Today by Rob Dunn)
The immune system is amazing too. It has many components. They are known as white blood cells, as opposed to red blood cells, which carry oxygen from the lungs to our cells. The main immune system is made up of lymphocytes and phagocytes. Lymphocytes are of two main types. B cells are the ones that produce antibodies to foreign invaders. They also communicate with the other kinds of immune cells. These are the T cells. T cells are responsible for destroying infected cells, call in other immune cells to help attack the invaders, and function in a regulatory manner. Phagocytes eat up foreign bacteria and release histamine to kill off such things like parasites. Then, there are neutrophils which also eat bacteria and break them down, mast cells which help to fight off allergens, and monocytes which are like the police of the bloodstream. They call in reinforcements, and turn into macrophages. The macrophages eat bacteria and recycle and remove cell debris. Finally, there are the natural killer cells. These cells cause “programmed” cell death to infected and tumor cells. (Information on immune cell types and functions was cribbed from https://www.newsmax.com/fastfeatures/immune-cells-types/2016/05/24/id/730498/)
The immune system is not a perfectly working system. It can either fail to fight an infection or other bodily invaders, or they can actually attack our own healthy cells. When the immune system attacks our own bodies what results is an autoimmune disease. One is rheumatoid arthritis, which attacks more than just the joints. There is the skin condition known as psoriasis, which up until recently was difficult to counteract until the class of drugs called biologics like Humira were developed. Psoriasis can also cause a form of arthritis. Crohn’s disease as mentioned above is another autoimmune disease that is now successfully treat with the biologics, especially if worms turn you off. The problem with biologics is they can cause other serious conditions like increased risk of infection, and some can induce a lupus syndrome or cause lymphomas and other conditions.
We are very fortunate if we have a working immune system. It protects us from all those nasties out there once they gain entry. Way to go immune system. When it is defective we will die of various infections or it will attack our own bodies, maybe eventually leading to death. (If you want to know more about the immune system and its working, just google it, and you will get a number of good web pages discussing it.)
Supposedly, just like snowflakes, no two human beings share the same fingerprints, not even identical twins. How they can be absolutely sure I always find myself asking? Have they really compared all the billions of people living, now and in the past? I find it strange if true.
Finally, I come to the most complex object we know about in the universe—the human brain. Three pounds of flesh, which is able to investigate itself. Whether or not we will ever be able to figure it all out to me is not determined; although, there are those that say it is impossible. Philosophically (wrongly in my opinion), it is deemed impossible for a thing to understand itself. Scientifically, it is just too complex for us to be able to figure it all out (which may be true, but not proven so).
The philosophical position is untenable because what is needed is empirical (scientific) evidence to prove that it is impossible. Doubtless, there have been many things that were deemed to difficult to understand, but have since become understood to a large degree. As an example: what is the world made of? Granted, we have never tried to tackle something so complex (more to follow), but we have been making great strides in our (scientists really) attempts to figure it out. We know a lot about its structure and how neurons functions and communicate along with many subsystems. We now consider perception as understood for the most part. Emotion and feeling is coming to be better understood as well; although, there is more work to be done. Even awareness, which is one of the keys to consciousness is beginning to be understood. While the complexity of the brain is certainly daunting, to throw up our hands and give up is not shown to be the best policy. Even if we never come to an understanding of the holy grail of the brain—consciousness—we are sure to develop a lot of understanding that will serve to benefit humankind if it is not misused.†
The complexity lies in that there are a hundred billion neurons in the brain (an average I suppose), and there are a hundred trillion (possibly more) synaptic connections between these neurons. Who actually counted them all? Some are local connections, and some are of longer distances between neurons. They can often be linked in circuits. They are clumped together in different structures, and these may make up systems and subsystems of the brain, such as the language centers (Broca’s and Wernicke’s areas). There are perceptual systems. There are structures that appear to be involved with memories and emotions. And, there are structures such as the amygdala, which is involved in attention and a whole bunch of other functions. Without our brain stem we would be biologically functionalless. And then there is the much vaunted prefrontal cortex, which is implicated in cognitive thought.
A good deal of these things are link up to each other. The prefrontal cortex and emotional functioning areas have numerous connections. This is one reason that thoughts and feelings often go together. We rarely have a thought without a feeling, and we rarely have a feeling without a thought. Awareness is produced in the connections between the amygdala, the brain stem, and other areas and structures. And, somehow or other the brain through its interactions with itself produces our sense of consciousness and self-consciousness.
It is really amazing that our brains allow us to accomplish so much. We are able to feed our faces, regulate the beating of our hearts and our breathing. The brain is involved in other visceral functioning too. One, which is connected with metabolism, is satiation (the feeling of being full and an indication that we should stop shoving it in). And, it allows for more amazing functions, such as thinking, feeling, and navigating our environments.
There is a lot more to be said about the brain of course; I only tried to highlight some important parts and functions. Some might ask, why I have not mentioned the mind? This is because as far as the brain is concerned it does not exist. “But hold on, certainly we have minds,” you say. I will agree that we experience consciousness, and this maybe what most people think that the mind is. Other than consciousness we are not aware of any mind like thing. Is there no role for the mind then? I think that the mind is a philosophical concept. Interesting to think about for sure, but it should not be the focus of science; it is a term of convenience.‡
Okay, the biological world is filled with weirdness. It contains cell functioning we are not aware of; to a large degree the material of our bodies is being continuously replace; there is metabolism turning food into pooh, allowing for the smooth functioning of our bodies; there is plant growth as well; there are extremophiles (strange denizens of world); of course, there is DNA containing the whole encyclopedia of life; much connected with DNA is development; do not forget about all those organisms on and in us; there is also the immune system; there is the strange phenomenon of nobody having the same identical fingerprints; finally, there is, the greatest of wonders, the brain.
If you do not find all this to be strange and fascinating, you might need to go out and find a self-help book to improve your imagination. The biological world is truly wondrous. It is all quite odd and very peculiar to me. It is bizarre at times. It all seems like a fantastic voyage.
³ For a handy chart of these organelles and their functions, where I got my information go to https://www.khanacademy.org/test-prep/mcat/cells/eukaryotic-cells/a/organelles-article.
º Personhood is usually used in philosophical discussions where ethics is involved. See Is Baxter a People Too? for a discussion of personhood.
* I explore the level of explanations we desire in how and why something works in my post – Could I Use a Little Reducing?
^ Crohn’s is one disease, which is understood to have arisen do to improved sanitation (known as the clean theory of disease, which posits that some diseases in modern cultures that people are susceptible to are the result of living in too clean of an environment, where they are not exposed to these diseases and do not form antibodies to them earlier on in life). Polio is suspected of being one of these diseases too. The cleanliness of households in the United States beginning in the early twentieth century left millions of Americans, mostly children, unexposed to the virus that causes it.
† This would be a topic for another blog post—should we pursue scientific and technological research?
‡ I have started a post exploring whether we have minds or not.